Tuesday, June 20, 2017

Mountain Lion Mark II – Laser-cut Planes

Teaching a summer projects building class at local university (College for Kids) for many years I have tried a wide variety of science related projects; originally it was all model airplanes. In the later years it has been a wide variety of projects such as model solar cars, water rockets, simple electric motor, mousetrap cars, syringe hydraulic arm, and model airplanes.  Often the projects were construction article on my Ideas-Inspire.com website and this was a way to test out how the projects worked out when students constructed them. The down side to using what was on my website was I created my own kits which took so much time, it did save money however. If a shop environment were available with more tools, students could do more of the work.


Mountain Lion Mk II





For this years’ class I decided I was going to purchase most of the kits using some of the money made from advertising on my website. What I learn should be helpful for teachers that would not have the time to create kits for even larger groups of students. The vendors I used were smaller companies that I like to support. 




This year I wanted to add a balsa and tissue covered airplane to the list of projects and was looking for a design where no sharp blades were needed. Doing an online search I came across Laser-cut Planes and the Mountain Lion Mark II which fit the requirements and was a reasonable price when purchased in bulk. A rather unique feature in the construction was that most pieces were temporarily held together with stickers, building boards or pins were not needed.












Other than glue, everything is included to build the airplanes including tissue for covering and rubber strip for motors.  For my sample plane I used Sigment model cement and CA for final assembly, tissue was adhered with glue stick.  Included are pattern sheets to assemble wing and stabilizer over but one set of complete instructions for the teacher.





I pressed the parts out of the laser cut sheets without using a knife at all, and I did no sanding. When placing the stickers over the joints I used one hand to push the joints together as tight as possible and put the sticker on with the other hand.  Out on the tips of the wing and stabilizer because of the direction of the grain it is rather fragile.

Note: 6-21-2017

For each wingtip there is a balsa doubler included to reinforce the weak spot because of the grain direction.






Bill Kuhl

Related Links

http://www.lasercutplanes.com/  - Mountain Lion Mk II and other kits

http://www.docfizzix.com - using mousetrap car kits from Doc Fizzix

http://www.everythinghobby.com - purchased rubber powered helicopters from local hobby shop





Thursday, June 15, 2017

E36 Free Flight 2017 Progress – Sometimes I go Backwards

If it was too easy it wouldn’t be so darn fun; at least that is how I feel about my faster climbing free flight models.  Adjusting somewhat slower climbing models like my e20 Sky Demon and the electric Sniffer provided me with some challenges but both are adjusted pretty well now but I am still adjusting the power pattern on the e36 Starduster. 


BMJR e36 Starduster


Last weekend I thought the climb looked really good and it was consistent, my attempt at setting 5 second DT did not do as well and the plane hit the ground hard enough to break the fuselage in half. It was a quick repair and it was still climbing in a consistent power pattern. I had originally put a lot of stab tilt in the stab mount thinking it was needed to get left glide. It turns out there was too much left glide so I kept putting shims under the low side. What I had not thought of was this was shimming the front of the stabilizer on both sides creating more positive incidence which gave the plane less climb which is what was needed.


E36 Starduster


With all the shims to get the stab level, the stab platform was only supporting the bottom of the stab in a couple of small spots.  So in my fix up for the next flying session I cut off all the shims and re-glued the stab platform level; it looked much better. I also made a magnetic hatch for the battery compartment.


Stab Tilt Diagram


Shimming to Make Level Again Created Positive Incidence


Stab Level Took Out Positive Incidence


I am slowly learning with any change, start with very short motor run and quick DT.  That is what I did and a good thing, the airplane was doing half a loop after launch and the turn was more to the right.  I tried launching more to the left but it was obvious it was going up too much. I had other things to do but I went flying again later and started shimming the front of the stab, the power pattern was getting better. Finally it dawned on me what was happening and I continued to add more shims. The flights were now very consistent. 


Magnetic Battery Cover





When I got home I put in a permanent shim and also a small shim for the motor. The glide has plenty of left; it is only in power phase that it wants to go right. Next time I will proceed very carefully with the new changes.  The more flying I do with these free flight models the more comfortable I am making trim adjustments and interpreting the  results.  

Bill Kuhl
http://www.ideas-inspire.com

http://www.bmjrmodels.com/free-flight/e-36/Starduster-E-36  BMJR Models Starduster e36

http://www.texastimers.com/  Texas Timers  eMAX timer and accessories

Thursday, June 8, 2017

Fishing Success and the Opportunity

My fishing success this year has really been a mix of good results and going home without catching a single fished; “skunked” is a common way of describing it.  Fishing for trout early in the season which is normally productive had me leaving without a single fish two times in a row, fishing at spots that I had caught fish before. It had me thinking about what had changed and what I could do to correct it.


I am doing mainly catch and release


Talking to other people I found that some people have had good success but also talking to land owner next to the water I had been fishing he told me lately he never sees anyone leaving with fish. From talking to people that know about the habitat that trout prefer I found out that some stream areas were filling in with sand which is bad for the eco system. When I tried fishing in stream areas that had a rocky bottom I started to catch fish again.


Brown Trout


When bass fishing season opened I tried casting a couple of times from shore of the small lake  a few blocks from my house just before sunset and again was skunked, same results from a pond that I normally catch bass in too.  Fishing there later into the evening at the pond I did have some luck. 





I find that success in many endeavors in life is dependent on finding the better opportunities. Google definition is “a set of circumstances that makes it possible to do something”.  A few days ago I was again fishing for largemouth bass in the evening at a lake close to my house with no luck at all. At the point when I was feeling a little frustrated I was about ready to go home but saw a young man fishing in the same general area and inquired about his fishing success. He told me it had been slow today but a few days ago he had caught a 5 pound bass in another area of the lake. I decided to try spots along the way to the area he had mentioned.

Big Bass

When I arrived at the mentioned spot I noticed a bunch of movement in the water just below the surface, I had never seen the fish this active before. Just down from this I noticed I noticed a blue heron in the water, no doubt doing some fishing also. I threw out my HooDoo lure just purchased from Hogline Baitshop and caught a fish on the first cast. Next cast and my drag is slipping like crazy, I knew I had a really large fish on. Besides the fish there was a bunch of weeds covering but I got it up on shore and pulled the weeds off. It was the biggest largemouth bass I had ever caught, my guess around 5 pounds. After taking a picture I released it and caught a few more slightly smaller fish until it was completely dark.


Blue Heron


Realizing I had possibly found a good opportunity from knowing the best time and place to fish I went back the next evening and caught another bass the same size and a few more.  I missed a day but when I tried same spot again I noticed very little ripples in the water and no blue heron fishing. The bass I caught were much smaller and less frequent. 


RC Sailplane Flying

In my model aviation hobby I watch the weather forecasts and look for predictions of cool morning temperatures that rise rapidly during the day which should be conducive to good thermal air current production for RC sailplanes or free flight models. If you are an investor in the stock market, finding the right opportunities is really important but often not easy.


When it comes to leisure activities finding the best opportunity isn’t everything, it is often just nice to just have the opportunity to do an activity you enjoy.

Bill Kuhl
http://www.ideas-inspire.com


Tuesday, June 6, 2017

Sniffer Electric Free Flight Report

In my hobby interests I try to use “adaptability” to enjoy what I have available to me in the local area. Locally we do not have an abundance of open area to fly free flight model airplanes. In the past I have flown small rubber powered models or gliders that if I lost it would not be too upsetting to me.  Somewhat larger free flight models to me can be more fun to build and challenging to get adjusted properly.




In my Build Report for the BMJR Sniffer I described the Sniffer kit that originally I was going to power with a Cox PeeWee .020 engine but decided to use a brushless electric motor and radio control for control of motor speed and dethermalizing (DT). I had thought it would be easy to connect the servo for rudder control but so far I am having more fun with an airplane that is almost free flight.




When I started flying the plane it flew right under power but changed to left for the glide but not always consistently so.  I added a rudder trim tab and forced the plane to fly to the left under power while maintaining a left glide. My concern was the plane might glide too much left but that does not appear to be a problem. The transition from power to glide is pretty smooth. When making trim adjustments it is so nice to be able to shut the motor down immediately or trip the DT to bring the plane down safely if it looks like a crash is likely.





Where I often fly there are many obstacles and if it looks like the glide will go over a building or tree I use the DT to bring it down before reaching the obstacle. This works pretty well except one time it came down into a chain link fence after the DT, no damage however.  If it is close to calm I will leave the power on until the Sniffer is pretty darn high. Most times it circles in the general area without drifting too much. When calm you can fly it around at reduced power and it will just circle around at like 30 feet high.





From my observation I think the propeller freewheeling in the glide has a rather detrimental effect on the glide, it also appears to cause the glide to be left. I say that as when I removed the propeller and did some test glides from a small hill the plane went straight. Spinning the propeller in the glide turns the motor which has a fair amount of friction. I know for better glide performance in P30 rubber power event people try to reduce that friction with their freewheel mechanisms.  I am going to look for a folding propeller for my motor.






This has been a fun project and gives me ideas for other sport models I could use RC DT on. Maybe a rubber powered model. 

Bill Kuhl








Tuesday, May 23, 2017

Behavior of Free Flight Airplanes & Little Girl With a Curl Syndrome

The more I build and fly free flight model airplanes, the more it appears that the models may have personalities like humans or animals do, that is characteristics that make each one somewhat unique.  Ultimately there has to be reasons based on design, trim adjustments, and accuracy in construction for the flight characteristics.   Some models appear to have a preference to turn one direction over the other in flight, trying to change that may not be easy.  With the smaller models it appears that the freewheeling propeller can change the direction of the glide either right or left. On my electric Sniffer model which has always had a preference to glide to the left I did some glides from a small hill with the propeller removed and the plane repeatedly glided straight.


Sniffer Electric Powered


This year my objectives are to build more accurate models, use methods to ensure nothing shifts in flight, and learn to adjust the models to perform in a consistent manner. I am guilty of wanting to get the airplane flying before finished with all of the little details such as keying the wing and stab so it cannot shift in flight.  I have also learned that changes in the thrust can make big differences in the flight pattern, example is with electric, some of the battery is used up rather quickly and the rpm drops, this could have a big effect on the flight power pattern if you keep flying without changing out the battery.


Sniffer Flying Well 

Recently I worked with adjusting my electric powered Sniffer free flight and think I made some real progress. To start with in the flying session I tried to force the plane to glide right and climb right with rudder tab. Too much right and it was not climbing, backed off on right rudder and the glide was too straight. 


With Proper Trim it Lands Almost Perfect

In desperation I put the rudder tab left, I was afraid the glide would be too much left but that appeared to be not the case. Now it climbed very consistent to the left and the glide was consistent left also. Flight after flight was darn near the same. I could let it get fairly high for the flying site and it would land close most of the time. 


Stab Keyed on Sky Demon e20 Electric

Ending this blog posts with some quotes about quirks of free flight models from people with a whole lot more knowledge and experience than myself: 


“I have built three 32 inch Brooklyn dodgers over the years.  The first one flew right-right, and was a great model. The second flew left- left and was also a great model. The third one flew right-left and no matter what I tried (including the directions) , it would not fly well on anything more than two 
thirds power. I threw it away.”

“--FF models of all types suffer from the little girl with the curl syndrome. When they are good, they are very very good, but when they are bad they are horrid. You do what you have to do to make them fly--although the universal advice is make just one change at a time. Some models never survive the trimming process, and other models soldier on for years of flying.”

“Cabin sport models-of which the Sniffer is a typical example- frequently seem to prefer L-L trim. Personally I fly them the way they want to fly naturally-which is usually L-L.....occasionally I've had a cabin model that preferred going R-and very rarely-one that was happy turning either way without any particular preference.....some were even the same design! [Vic Smeed 'Tomboy' , 40" simplex and Modelair 'Hummingbird']......I think in practice it results from the subtle interaction of thrustline, cabin height and fin area....”

Bill Kuhl



Tuesday, May 16, 2017

Background in Free Flight - Part II

Up until last year my free flight flying had been smaller rubber powered models such as the Peck Sky Bunny, AMA Maxi Jr., and a couple of scale type models such as Guillows Super Cub. 

Guillow's Super Cub chased by a Gull

A couple of years ago I decided to try a free flight discus launched glider the  Maxima.  Even though I had launched RC discus gliders, I had a something to learn about launching and more critical adjusting the glider. It crashed many times in the beginning. As I got it dialed in better, the flights kept improving and I saw it circling upward in thermals fairly often.  

To not lose it until the end of the flying season I was really lucky. It was stuck in a tree but blew down.  It completely flew over a bunch of trees and landed next to a road. Another time it flew over a small pond.  When I lost it the DT must have hung up and it circled for a long ways until over a cornfield. 

Maxima DLG


Wind Blew it Down

I think it was the same year I had bought components for an e36 electric free flight from Texas Timers. Progress on a Pearl e202 model was really slow but before the end of the flying season I decided I would put the electric components in a Starduster ½ A free flight someone had given me.


1/2 A Starduster Electric Components

Not knowing anything about powered free flight, it flew pretty well for me. Only one time did it crash, probably because the wing was not on straight or a bad launch. 


Rudder Only RC Crash




Pearl e202 Successful Flight no RC

The next season I finished up the Pearl e202 but with such a tiny flying site, I added RC equipment for rudder control. I really didn’t know what a proper test glide should look like and did not have enough decalage.  Even though I could steer, it still crashed without a way to give it up.  After repairs and getting the proper trim it flew good with only rudder control.


Jack Murphy Launching

About this time I was going as a competitor to my first Nats in Muncie Indiana, I took the RC equipment off.  My thought was getting there a day early someone could help me get it adjusted. 


Dave Edmundson

As luck would have Jack Murphy parked right next to us, I had come with Dave Edmundson from Minnesota. Jack helped me and I got in some flights. 


Nats with Jim Jennings Jr. and Dohrm Crawford



At the Nats I met so many super people, many I had only known from the Internet such as Dohrm Crawford. Dohrm helped me so much in getting my e36 flying. He borrowed a heat gun from someone and we straightened out the wing. On another day it made a very nice flight with over 10 second run.

For the competition day I launched it on a short run with a quick DT but the stab did not go up far enough, it just kept circling in a thermal for maybe a couple of minutes but it did come down on the edge of the field. Dohrm and Jim Jennings Jr. redid the DT system for me.


I met a bunch of people that I only knew through the Internet at the Nats, pictures of a few of them below.

Hank Nystrom - Timer Guy


Hank Sperzel


Bob Hanford
Dan Berry

Chuck Powell and Jim O'Reilly
George Bredehoft

Lee Hines

Norm Furutani

At the Nats I had the chance meet many of the great glider flyers including the designer of my Dynomite TLG Stan Buddenhom. My performance was just okay, I was not patient waiting for good air.

Stan Winding Up


Jan Winding Up

Tim
My Dynomite DLG at 2016 Nats below




For 2017 I built several competition free flights and also experimented with other ideas.

A friend who flies RC sailplanes thought I might be more interested in some CO2 motors, so he sold them to me.  The first plane I put the motor in did not seem to have enough wing area but this plane climbs very easily. So much so I installed fuse DT system. 

CO2 Engine Free Flight


I purchased the BMJR Sniffer kit originally thinking I would try a glow powered free flight again because I had a couple of Cox PeeWee .020 engines. Researching the PeeWee 30 event that this plane would qualify for I realized it would not be a competitive airplane so decided I would install a small brushless electric motor and use RC equipment to control the motor speed and to be able to DT on demand. This way I could fly from a smaller field and bring the plane down whenever I wanted to. It is working well for that.

BMJR Sniffer


So much I have skipped through, look for video with many more images and video.

Bill Kuhl